1. Field of the Invention
This invention pertains to robotic grippers and more particularly to grippers driven by electric motors. Grippers are used to grasp an object so the object can be held or moved to a desired location and orientation.
2. Description of Prior Art
The robotics and automation industry heavily relies on robotic grippers for grasping objects such as mechanical or electrical components so those components can be moved from one place to another or held in a particular orientation. Grippers of various sizes, shapes, and configurations have been used to handle objects ranging in size from as small as electronic components to as large as satellites deployed in or retrieved from low-earth orbit. Grippers can be opposing jaws, ensnaring wires that wrap around a grappling pin, anthropomorphic, hand-like designs, as well as many other specialized shapes.
Grippers may be mounted on highly articulated robotic arms having multiple degrees of freedom, or simple automation devices that may have only one or two degrees of freedom. Generally, highly articulated grippers and robotic arms require complicated control and power systems. The majority of grippers currently used in the automation industry are pneumatically powered. This is primarily due to the significantly greater power obtainable from a pneumatically driven gripper compared to an electrically driven gripper of similar size. Disadvantages of prior versions of electrical grippers include being large, complex, delicate, or expensive.
The present invention uses an innovative design to produce an electrically driven gripper with high gripping power in a small and relatively inexpensive package. The gripper of the present invention comprises an electrically driven gripper having a housing, a motor attached to the housing, a cam engaged to the motor, a pair of opposing jaws slidingly mounted to the housing, a cam follower secured to one of the jaws and in sliding contact with the cam; and a spring configured to impart a force to the jaws such that the jaws are pulled toward each other. The motor drives the cam to force the jaws to maximum open position. Continued rotation of the cam allows the spring to pull the jaws closed to grasp an object with the jaws. Sensors mounted to the housing determine whether the jaws are in an open or closed state. A simple circuit on a printed circuit board mounted to the housing is used to control the electric motor.